Blockade of miR-140-3p prevents functional deterioration in afterload-enhanced engineered heart tissue

Integrated Analysis of lncRNA-miRNA-mRNA Regulatory Network in Rapamycin-Induced Cardioprotection against Ischemia/Reperfusion Injury in Diabetic Rabbits

The inhibition of mammalian target of rapamycin (mTOR) with rapamycin (RAPA) provides protection against myocardial ischemia/reperfusion (I/R) injury in diabetes. Since interactions between transcripts, including long non-coding RNA (lncRNA), microRNA(miRNA) and mRNA, regulate the pathophysiology of disease, we performed unbiased miRarray profiling in the heart of diabetic rabbits following I/R injury with/without RAPA treatment to identify differentially expressed (DE) miRNAs and their predicted targets of lncRNAs/mRNAs. Results showed that among the total of 806 unique miRNAs targets, 194 miRNAs were DE after I/R in diabetic rabbits. Specifically, eight miRNAs, including miR-199a-5p, miR-154-5p, miR-543-3p, miR-379-3p, miR-379-5p, miR-299-5p, miR-140-3p, and miR-497-5p, were upregulated and 10 miRNAs, including miR-1-3p, miR-1b, miR-29b-3p, miR-29c-3p, miR-30e-3p, miR-133c, miR-196c-3p, miR-322-5p, miR-499-5p, and miR-672-5p, were significantly downregulated after I/R injury. Interestingly, RAPA treatment significantly reversed these changes in miRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated the participation of miRNAs in the regulation of several signaling pathways related to I/R injury, including MAPK signaling and apoptosis. Furthermore, in diabetic hearts, the expression of lncRNAs, HOTAIR, and GAS5 were induced after I/R injury, but RAPA suppressed these lncRNAs. In contrast, MALAT1 was significantly reduced following I/R injury, with the increased expression of miR-199a-5p and suppression of its target, the anti-apoptotic protein Bcl-2. RAPA recovered MALAT1 expression with its sponging effect on miR-199-5p and restoration of Bcl-2 expression. The identification of novel targets from the transcriptome analysis in RAPA-treated diabetic hearts could potentially lead to the development of new therapeutic strategies for diabetic patients with myocardial infarction.

Evaluation of left ventricular dysfunction by three-dimensional speckle-tracking echocardiography and bioinformatics analysis of circulating exosomal miRNA in obese patients

BACKGROUND

Obesity is an independent risk factor for cardiovascular disease and affects the human population. This study aimed to evaluate left ventricular (LV) dysfunction in obese patients with three-dimensional speckle-tracking echocardiography (3D-STE) and investigate the possible related mechanisms at the exosomal miRNA level.

METHODS

In total, 43 participants (16 obese patients and 27 healthy volunteers) were enrolled. All subjects underwent full conventional echocardiography as well as 3D-STE. Characterization and high-throughput sequencing for the isolated circulating exosomes and the differentially expressed miRNAs (DEMs) were screened for target gene prediction and enrichment analysis.

RESULTS

Obese patients had significantly lower global longitudinal strain (GLS) (-20.80%±3.10% vs. -14.77%±2.05%, P < 0.001), global circumferential strain (GCS) (-31.63%±3.89% vs. -25.35%±5.66%, P = 0.001), global radial strain (GRS) (43.21%±4.89% vs. 33.38%±3.47%, P < 0.001), and indexed LV end-diastolic volume (LVEDV) [38.07mL/m2 (27.82mL/m2-9.57mL/m2) vs. 24.79mL/m2 (21.97mL/m2-30.73mL/m2), P = 0.002] than healthy controls. GLS (ρ = 0.610, P < 0.001), GCS (ρ = 0.424, P = 0.005), and GRS (ρ = -0.656, P < 0.001) indicated a moderate relationship with body mass index (BMI). In obese patients, 33 exosomal miRNAs were up-regulated and 26 exosomal miRNAs were down-regulated when compared to healthy controls (P < 0.05). These DEMs possibly contribute to obesity-associated LV dysfunction through the PI3K-Akt signaling pathway. Important miRNAs, including miR-101-3p, miR-140-3p, and miR-99a-5p, have clinical utility in predicting early obesity-related myocardial injury.

CONCLUSIONS

The global strain obtained from 3D-STE can sensitively detect the decrease in LV myocardial function in obese patients. Key miRNAs and pathways provide a new theoretical basis and targets of action for studying obesity-induced LV dysfunction.

TRIAL REGISTRATION

In accordance with the World Health Organization (WHO) definition of a clinical trial, this study does not include human health-related interventions. This study was carried out at the General Hospital of Ningxia Medical University after obtaining institutional ethical approval (KYLL-2022-0556) and written informed consent from all participants.

Tissue engineering techniques for iPSC derived three-dimensional cardiac constructs

Recent developments in applied developmental physiology have provided well-defined methodologies for producing human stem cell derived cardiomyocytes. Cardiomyocytes produced in this way have become commonplace as cardiac physiology research models. This accessibility has also allowed for the development of tissue engineered human heart constructs for drug screening, surgical intervention, and investigating cardiac pathogenesis. However, cardiac tissue engineering is an interdisciplinary field that involves complex engineering and physiological concepts, which limits its accessibility. This review provides a readable, broad reaching, and thorough discussion of major factors to consider for the development of cardiovascular tissues from stem cell derived cardiomyocytes. This review will examine important considerations in undertaking a cardiovascular tissue engineering project, and will present, interpret, and summarize some of the recent advancements in this field. This includes reviewing different forms of tissue engineered constructs, a discussion on cardiomyocyte sources, and an in-depth discussion of the fabrication and maturation procedures for tissue engineered heart constructs.

KCNQ1OT1 Exacerbates Ischemia-Reperfusion Injury Through Targeted Inhibition of miR-140-3P

Potassium voltage-gated channel subfamily Q member 1 opposite strand 1 (KCNQ1OT1), a long non-coding RNA found in the KCNQ1 locus, has been evidenced to play important roles in the aggravation of inflammatory and oxidative stresses under hypoxia, but whether and how KCNQ1OT1 contributes to neuronal damages in the cerebral ischemic stroke remains unknown. In the present study, we found a dominant upregulation of KCNQ1OT1 both in the plasma of cerebral ischemia patients and in an oxygen-glucose deprivation and reperfusion (OGD/R) model in PC12 cells. KCNQ1OT1 knocking-down significantly ameliorated the inflammation, oxidative stress, and cell apoptosis induced by OGD/R. We further demonstrated that KCNQ1OT1 directly bound to and suppressed the expression of miR-140-3p. Overexpressing miR-140-3p significantly alleviated both the inflammation, oxidative stress, and cell apoptosis in OGD/R, while all those cytoprotective effects of miR-140-3p-overexpression were hindered by the co-overexpression of KCNQ1OT1. Furthermore, we found a direct interaction between miR-140-3p and the hypoxia-inducible factor-1α (HIF-1α), which was suppressed by the upregulation of KCNQ1OT1 in OGD/R. Our results indicate that KCNQ1OT1 exacerbates cerebral ischemia-reperfusion injury by targeted binding to miR-140-3p, thus interfering its direct interaction with HIF-1α. These data provide novel therapeutic targets in the cerebral ischemic stroke.

Effects of the Delta Opioid Receptor Agonist DADLE in a Novel Hypoxia-Reoxygenation Model on Human and Rat-Engineered Heart Tissue: A Pilot Study

Intermittent hypoxia and various pharmacological compounds protect the heart from ischemia reperfusion injury in experimental approaches, but the translation into clinical trials has largely failed. One reason may lie in species differences and the lack of suitable human in vitro models to test for ischemia/reperfusion. We aimed to develop a novel hypoxia-reoxygenation model based on three-dimensional, spontaneously beating and work performing engineered heart tissue (EHT) from rat and human cardiomyocytes. Contractile force, the most important cardiac performance parameter, served as an integrated outcome measure. EHTs from neonatal rat cardiomyocytes were subjected to 90 min of hypoxia which led to cardiomyocyte apoptosis as revealed by caspase 3-staining, increased troponin I release (time control vs. 24 h after hypoxia: cTnI 2.7 vs. 6.3 ng/mL, ** p = 0.002) and decreased contractile force (64 ± 6% of baseline) in the long-term follow-up. The detrimental effects were attenuated by preceding the long-term hypoxia with three cycles of 10 min hypoxia (i.e., hypoxic preconditioning). Similarly, [d-Ala2, d-Leu5]-enkephalin (DADLE) reduced the effect of hypoxia on force (recovery to 78 ± 5% of baseline with DADLE preconditioning vs. 57 ± 5% without, p = 0.012), apoptosis and cardiomyocyte stress. Human EHTs presented a comparable hypoxia-induced reduction in force (55 ± 5% of baseline), but DADLE failed to precondition them, likely due to the absence of δ-opioid receptors. In summary, this hypoxia-reoxygenation in vitro model displays cellular damage and the decline of contractile function after hypoxia allows the investigation of preconditioning strategies and will therefore help us to understand the discrepancy between successful conditioning in vitro experiments and its failure in clinical trials.